All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
Everyone who is obliged to slaughter a sheep for violating any restrictions of Ihram, or abandoning any obligatory act of Hajj, should slaughter a sheep within the sanctuary of Al-Haram (i.e. in Makkah). Thus, slaughtering outside Al-Haram is not sufficient. This is the opinion of the majority of Muslim scholars.
Allah knows best.